ABUJA (Reuters) - Nigerian President Muhammadu Buhari is recuperating fast and will return home shortly, his deputy said on Wednesday after visiting the head of state in London where he has been on prolonged sick leave.

Yemi Osinbajo’s brief and unannounced trip has revived speculation about Buhari’s health and whether he will be able to stand for re-election in 2019. The details of his illness have not been made public.

“He is in very high spirits, he is recuperating very quickly and we had a very long conversation. We spoke for well over an hour. His humour is all there. He is doing well,” said Osinbajo, who is acting president.

“We discussed wide-ranging issues. I can’t go into specifics,” he said in his first public comments after returning to Abuja on Wednesday morning. Osinbajo then chaired a weekly cabinet meeting.

When Buhari, 74, left Abuja for London on May 7, his second trip abroad for health reasons, he handed over power to Osinbajo, who according to the constitution would assume the presidency should Buhari be unable to continue.

Osinbajo is already being talked about in the capital as a potential nominee for the 2019 presidential election in Nigeria, sub-Saharan Africa’s largest economy and energy producer.

QUESTIONING THE NARRATIVE

A thin-looking Buhari was last seen in Nigeria on state television in early May, just hours before he flew to Britain, welcoming a group of 82 girls released by the Islamist militant group Boko Haram.

Buhari’s first trip to London for health reasons was in January and lasted nearly two months.

The Nigerian public’s view of Buhari’s situation has turned sceptical. As the trickle of information about the president’s health, which used to include photographs of meetings in London, dries up, some are questioning the official narrative.

“I don’t know, unless they show it to us on television or through anything, that both of them (Buhari and Osinbajo) are meeting,” said Adeleke Ogunlana, a businessman in Lagos.

“I don’t believe they met at all.”

With the economy now in its second year of recession, the first in a quarter of a century, others asked whether a sickly person should be at the helm.

“We want a healthy, vibrant president who is sound mentally and physically to be able to handle the problems facing the country,” said Emeka Iloabuchi, a Lagos-based marketer.

“The president as far as I am concerned should leave the office, should resign honorably so that the people of Nigeria can have a man that is healthy.”

AVOIDING POLITICAL INFIGHTING

Nigerian officials have sought to avoid a scenario seen in 2010 when political infighting broke out during the lengthy illness of then-President Umaru Yar‘Adua.

Osinbajo has been given full powers to act during Buhari’s absences, in contrast to predecessor Goodluck Jonathan who only took over after Yar‘Adua’s death in 2010 ended the power vacuum.

Investors have welcomed Osinbajo, a Christian lawyer from the commercial capital Lagos in southwest Nigeria who is seen as more business-friendly than Buhari.

But the long-term risk is that the Muslim north, where Buhari hails from, might not accept Osinbajo as a permanent solution if the president became incapacitated at some point.

Traditionally in Nigeria, the leadership rotates between north and south to ensure a balance in a country evenly split between Muslims and Christians.

Jonathan, a Christian from the south, upset many northerners by refusing to give way to a northern candidate in 2010. Many northerners had felt there should have been another northern presidential term after Yar‘Adua’s premature death.